Sept 14 (Reuters) - U.S. stocks fell back on Friday after President Trump instructed aides to proceed with tariffs on about $200 billion in Chinese products, despite Treasury Secretary Steven Mnuchin's attempts to restart talks with Beijing.

A source familiar with the situation confirmed stories initially carried by both Bloomberg and Fox News on the moves by the White House.

Wall Street, which had been trading marginally in positive territory on the back of a rise in U.S. Treasury yields above 3 percent, reversed.

"If Trump is willing to go ahead with the tariffs then that is significant enough to sour markets," said Bryan Reilly managing director at CIBC Private Wealth Management in Boston, Massachusetts.

"Should this trade uncertainty prevail, then sentiment only has one way to go from here and that is down."

At 12:39 a.m. ET the Dow Jones Industrial Average fell 0.17 percent to 26,102.37, the S&P 500 0.15 percent to 2,899.71 and the Nasdaq Composite 0.26 percent to 7,992.72.

Financial stocks held on to their gains and were last up 0.52 percent. Only three of the 11 major S&P sectors were higher.

Also weighing on utilities was NiSource, which tumbled 9.9 percent after fire investigators said they suspected the company's unit, Columbia Gas, was linked to a series of gas explosions in Boston suburbs on Thursday.

The energy sector was up 0.69 percent, making it the best performing group on the day.

Walmart dropped 0.5 percent after Goldman Sachs raised questions around the purchase of a majority stake in India's Flipkart.

L Brands Inc jumped 4.8 percent after the owner of Victoria's Secret said it would close all 23 Henri Bendel stores and its website in January.

Declining issues outnumbered advancers for a 1.18-to-1 ratio on the NYSE, but advancing issues outnumbered decliners by a 1.19-to-1 ratio on the Nasdaq.

The S&P index recorded 45 new 52-week highs and no new lows, while the Nasdaq recorded 100 new highs and 48 new lows. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Shounak Dasgupta and Arun Koyyur)